Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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S~CURITY DOCUMENT HAVING SBCURE BINDING MEANS
AND METHOD OF MAXING SAME
Fi-ld of the Invention
S This invention relates to security documents, such as
passports, and in particular to the binding means used to hold
in place the pages of the document. In accordance with the
invention the binding means provides security to the document to
protect it against tampering.
B~c~ground
Security documents such as passports often take the
form of a booklet consisting of a number of inner pages, to which
visas may be applied, and an identity page containing the
bearer's personal details and photograph. Typically the identity
page is covered by a transparent laminate sheet to protect and
secure the data on the sheet.
However, such lamination of the identity sheet does not
provide full security to the document because it is possible to
unravel or otherwise manually remove the stitched binding of the
passport, remove the identity sheet and replace it with another
and then restitch the pages of the passport back together again.
This i6 because the preferred method of manufacturing such a
security document is to assemble the individual preprinted inner
pages and laminate sheet, and then sew them together with a
cotton or synthetic thread. A reinforcing tape over the top
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page, along the stitching line, is sometimes also sewn in to
prevent the stitches from tearing the pages. A durable cover is
then bonded to the outer pages and the entire assembly is trimmed
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or diecut to the desired final size. The several steps`of this
manufacturing method are, in practice, combined into a continuous
manufacturing process.
In the case of a passport, a number of means have been
used to maintain the integrity of the stitching over the life of
the passport which may be up to 10 years, including the use of
complicated stitching techniques and the application of adhesives
to the thread immediately after sewing. However, such methods
increase the manufacturing time and cost significantly. It is
therefore advantageous to provide a simple means of binding
security documents, in a secure manner, according to the
invention claimed herein.
8u~o~ry of the Invent~on
In accordance with the invention there is provided a
lS security document comprising a plurality of sheets held together
by means of stitching. The stitching is comprised of successive
loops of thread wherein at least portions of the thread of a
plurality of the loops is fusible and those portions may be or
have been fused to prevent unravelling or other form of manual
removal of the stitching. Preferably the stitching is chain
stitching and each loop thereof is comprised of two threads, at
least one of which is fusible, and portions of the two threads
are fused together.
The invention further provides a method of making a
security document comprised of a plurality of sheets, the method
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comprising the step of stitching the sheets together using at ~ ;
least one fusible thread whereby at least portions of the thread ~- ~
may be caused to fuse on the application of heat to the thread ~ `
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and thereby prevent unravelling or other form of manual removal
of the stitched thread.
DescriLption of tho Drawing~
Figure 1 is a schematic illustration of the assembly
and stitching of a security document in accordance with the
invention.
Figure 2 is a plan view of chain stitching showing the
arrangement of the two threads used therefor.
Figure 3 is a plan view of lock stitching showing the
arrangement of the two threads used therefor.
Figure 4 is a schematic illustration of the folding of
a security document following the stitching step illustrated by
Figure 1.
Figure 5 is a schematic illustration of a security
document, of the type shown in Figure 4, passing through a
laminating machine.
D-t~ d D-scription of th- Inv-ntion
Figure 1 illustrates the assembly and stitching of a
security document 5, being a passport in the embodiment
illustrated. The components of the security document, comprising
a plurality of sheets 40,50, are collated in the conventional
manner in preparation for the binding process. The sheets of the
passport shown include preprinted sheets 40 and a pressure
sensitive or heat activated laminate sheet 50.
A Singer 300 W101 (trade-mark) sewing machine (not
shown) is fitted with a guiding mechanism to permit accurate
placement of the needle 10 and stitching 30 relative to the edge
of the sheets 40,50. To b:lLnd the sheets together the sewing
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method known as saddle sewing is used in Which the needle 10 is
passed through the center of the sheets 40,50 which will become
the spine 70 of the finished document 5 as shown by Figure 4.
A reinforcing tape 60 is, preferably, also stitched along the
spine 70 and may be positioned to the spine area prior to
stitching by using an adhesive (e.g. an adhesive-backed tape).
By using a reinforcing tape 60 accordingly the stitching 30 is
less likely to tear the sheets 40. The needle 10 is loaded with
a fusible thread. Thread supplied by Coates and sold under the
trade-mark StitCh and Fuse, having a melt temperature of 173F,
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is used by the inventor. The looper, if chain stitching is used,
may also contain the same or a dissimilar thread. Similarly, if
lock stitching is used the bobbin thread may also contain the
same fusible thread or, instead, a dissimilar thread. For a
dissimilar thread cotton, polyester, polypropylene, non-fusible
nylon or a blend thereof may be selected.
Figure 2 illustrates the configuration of the chain
stitch and Figure 3 illustrates the configuration of the lock
stitch. The chain stitch method is usually preferred for use
because the looper can be fed from a lengthy supply of thread to
match that of the needle thread whereas the bobbin thread
required for lock stitching holds only a shorter, more limited
supply Of thread. ThUS, the bobbin must be filled with thread
more frequently than the needle thread in the case of lock
stitching. As shown by Figure 2, the looper thread 15 and needle
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thread 10 form a connected series of loops. From the top side
22 of the document adjacent the tape 60 both the looper and '~
needle threads 15,10 are visibl From the bottom side 28 of the
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document only the needle thread 10 is visible. Alternatively
lock stitching, in which the needle thread 10 and the bobbin
thread 18 form a series of linked loops, may be employed.
The collated sheets 40,50 are continuously loaded into
the sewing machine and collectively sewn according to the
foregoing. The sheets 40,50 are cut to the size desired for the
intended security document. Following the sewing step sufficient
heat is applied to the thread 10 to melt and fuse it. This is
done by the inventor by means of directing a jet of hot air, at
10375F, from a hot air gun such as a Leister 801-3000 (trade-mark)
at the stitched threads for a period of 2.5 seconds per book to
ensure the thread is fused. The air temperature used can be
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altered, as necessary for the application, to suit productionrequirements. A durable cover (not shown) may then be applied
to the cut sheets and the passport document 5 finished by folding
the sheets 40,50 and cover along the spine 30 as shown by Figure
4.
The heat fusing of the thread 10 causes the thread
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fibers of the heated portions of the thread 10 to melt into a
homogeneous mass causing them to adhere to the adjacent thread,
being in the case of chain stitching the looper thread 15, and
in the case of lock stitching the bobbin thread 18. This then
results in an irreversible closing of the affected thread loops
of the stitching and prevents unravelling or other form of manual
removal of the stitching. The fusing of the thread 10 also
provides the advantage that the usual need for backstitching, to
prevent unravelling of the stitching at the ends of the document, -
is no longer necessary since the fusing itself prevents such.
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Alternatively, particularly in the making of passport
documents, fusing of the thread may, advantageously, be left for
completion at the time the passport is issued and the laminate
sheet 50 is heat fused 9o to its adjacent printed sheet 40 by
means of a laminator 80 as shown in Figure 5. This would avoid
duplication of the required step of heating the sewn sheets to
fuse the thread. (This assumes that a heat activated laminate
sheet 50 is used, for example the laminate material manufactured
by Transilwrap Company and provided under the trade-mark
Transkote.) The laminate sheet 50 of passport documents is fused
to the adjacent personal data sheet 40 only after the data sheet
40 is completed with the passport holder's personal particulars
just prior to issuance of the passport to the holder. A
laminator such as the General Binding Corporation 1000 P.L.A.
(trade-mark), set to an external temperature of 180F, will
simultaneously laminate the sheets 40,50 and fuse the thread to
secure the binding of the security document.
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